TECH: TORQUE SHOP #6

This is­sue’s Q&A ar­ti­cle an­swers three ques­tions about park­ing brakes.

Torque (Singapore) - - CONTENTS -

This is­sue’s Q&A ar­ti­cle an­swers three ques­tions about park­ing brakes.

I plan to get a car. I re­alise that many new cars to­day have elec­tronic park­ing brakes. It ap­pears to me that tra­di­tional hand­brakes are safer since they are man­u­ally op­er­ated and not sub­ject to elec­tri­cal or elec­tronic fail­ures.

Also, in case I have to per­form an emergency stop, it is eas­ier for my hand to grab and yank the hand­brake than for my fin­gers to seek out and fid­dle with a small lever to op­er­ate the elec­tronic park­ing brake. Are hand­brakes safer? More and more car mak­ers are opt­ing for elec­tronic park­ing brakes be­cause it frees up space in the aisle be­tween the front seats.

From a safety point of view, the park­ing brake should not be re­lied on for emergency stops. You should in­stead slam on the brake pedal with all your might and main­tain the pres­sure un­til the car is sta­tion­ary. Your hands should be on the steer­ing wheel, so you can steer the car away from dan­ger while brak­ing hard (pos­si­ble only with cars which have anti-lock brak­ing sys­tems). Hav­ing one hand on the park­ing brake lever will com­pro­mise this cru­cial ma­noeu­vre, which can make a dif­fer­ence be­tween life and death.

Hand­brake turns, ad­mit­tedly, are eas­ier to do with a phys­i­cal lever. But un­less you are a pro­fes­sion­ally trained body­guard or a rally driver, you should not at­tempt hand­brake turns and es­pe­cially not on pub­lic roads.

The park­ing brake is what its name sug­gests – to stop a ve­hi­cle from rolling off when parked. For this role, an elec­tronic sys­tem is bet­ter since it will al­ways ap­ply the cor­rect pres­sure – some­thing that is not al­ways the case with a hand-op­er­ated lever.

As for fail­ures, most elec­tronic or elec­tri­cal sys­tems in a car have built-in fail-safes. That is to say, if a com­po­nent fails (or in some cases, is about to fail), the driver will be warned. You do not get that with a con­ven­tional hand­brake. I re­cently pur­chased a sec­ond-hand 2008 Toy­ota Camry. This car comes with a foot-op­er­ated park­ing brake

AN ELEC­TRONIC PARK­ING BRAKE SYS­TEM FREES UP SPACE IN THE AISLE BE­TWEEN THE FRONT SEATS.

in­stead of a hand­brake. On a slope, I am able to man­age a car from go­ing back­wards us­ing the typ­i­cal hand­brake and ac­cel­er­a­tor. How do I do so with a foot­brake? I have been taught to use only one foot for the brake pedal and ac­cel­er­a­tor pedal. With an au­to­matic trans­mis­sion, the engine is al­ways cou­pled to the driven wheels as long as the trans­mis­sion lever is in one of the drive modes (whether for­ward, re­verse or man­u­als­e­lect). Hence, the car will not roll back­wards on a slope when you re­lease the brakes. It may ei­ther creep up­hill or stay sta­tion­ary – un­less the slope is very steep.

Even then, the trans­mis­sion pro­vides enough torque to de­lay a back­slide. You should put your left foot on the brake pedal and re­lease it as you ap­ply ac­cel­er­a­tion with your right foot.

For cars with a robo­tised-clutch or dou­ble-clutch gear­box, the clutch is dis­en­gaged when­ever the car is at a stand­still, even if the gear se­lec­tor is in Drive.

On a slope, the car could roll back. So you must hold the brake pedal with your left foot and re­lease only as you ac­cel­er­ate to move off. What you should never do with th­ese trans­mis­sions is re­lease the brakes and let the trans­mis­sion hold the car on the slope. This will cause the clutch to slip. If this hap­pens reg­u­larly, it will lead to pre­ma­ture wear.

There is no rule that says you can­not use your left foot for the brake pedal. How safe is it to leave a car’s au­to­matic trans­mis­sion in Park (P) po­si­tion with­out en­gag­ing the park­ing brakes? If there is no me­chan­i­cal flaw in the car, it should not roll away in Park. But if the auto gear­box is de­fec­tive, leav­ing the lever in P may not lock the ve­hi­cle in po­si­tion.

There are in­stances when a trans­mis­sion’s D (Drive) or R (Re­verse) does not en­gage ei­ther. This may be a link­age prob­lem. The same thing could hap­pen in P (Park), rare as it may be.

So to be safe, it would be best to en­gage your car’s park­ing brakes and turn off the engine, even if you are just leav­ing the ve­hi­cle mo­men­tar­ily.

JUNE 2018

More and more cars put their park­ing brakes at the driver’s fin­ger­tips, and some cars can even en­gage/ dis­en­gage their park­ing brakes au­to­mat­i­cally. JUNE 2018

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